V. L. Gein

Synthesis and antimicrobial activity of methyl-7-aryl(heteryl)-6-(2-thienoyl)-4,7- dihydrotetrazolo[1,5-a]pyrimidine-5-carboxylates

Eighteen methyl-7-aryl(heteryl)-6-(2-thienoyl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine-5-carboxylates (I – XVIII) have been synthesized via the interaction of methyl esters of acylpyruvic acids with a mixture of aromatic or heterocyclic aldehydes and 5-aminotetrazole monohydrate. The proposed structures of the synthesized compounds were confirmed by IR spectroscopy and PMR spectrometry. Several compounds have been tested for antimicrobial activity.

Synthesis and Antimicrobial Activity of 3-Hydroxy- and 3-Arylamino-5-aryl-4-acyl-1-(pyridyl)-3-pyrrolin-2-ones

Previously we reported on the synthesis of 3-hydroxy-3pyrrolin-2-ones containing aromatic substituents in position 5 and aroyl [1 – 4] or arylsulfonyl [2, 5] in position 4. It was found that these compounds possess, depending on the character of substituent in position 1 of the heterocycle, antimicrobial [6], antiviral [6, 7], analgesic [6], and antiamnesic [8] properties. For elucidating the influence of the character of substituents in position 1 on the biological activity of 3-pyrrolin-2ones, especially on their antimicrobial properties, it was of interest to introduce a pyridine residue into this position. In order to obtain 5-aryl-4-acyl-1-(2-pyridyl)-3-hydroxy-3-pyrrolin-2-ones (I – XV), we have studied the reactions of acylpyruvic acid esters with a mixture of aromatic aldehydes and 2-aminopyridine or 5-bromo-2-aminopyridine. R = H (XVI, XVII), CH3 (XVIII), Br (XIX), C2H5O (XX), CH3O (XXI); R 1 =C H 3 (I – V, XVI), C6H5 (VI – XI, XVII – XXI), 4-BrC6H4 (XII, XIII),

Synthesis and antimicrobial activity of 1-(4-hydroxyphenyl)-4-acyl-5-aryl-3-hydroxy-3-pyrrolin-2-ones

The reaction of methyl esters of acylpyruvic acids, 4-aminophenols, and aromatic aldehydes leads to the formation of 1-(4-hydroxyphenyl)-4-acyl-5-aryl-3-hydroxy-3-pyrrolin-2-ones. The proposed structures of the synthesized compounds were confirmed by IR and PMR spectroscopy. The antibacterial activity of some of the newly synthesized compounds was studied.

Synthesis and antibacterial activity of 1-alkoxyalkyl-5-aryl-4-acyl-3-hydroxy-3-pyrrolin-2-ones

Reactions of methyl ethers of acylpyruvic acids with a mixture of aromatic aldehyde and 2-methoxyethylamine or 3-isopropoxypropylamine were used to synthesize a series of 1-alcoxyalkyl-5-aryl-4-acyl-3-hydroxy-3-pyrrolin-2-ones possessing antibacterial activity.

Synthesis and antibacterial activity of 1-(5-aryl-4-benzoyl-3-hydroxy-2-oxo-3-pyrrolin-1-yl)-2-(3-benzoylmethylene-2-oxopiperazin-1-yl)ethanes

A series of l-(5-aryl-4-benzoyl-3-hydroxy-2-oxo-3-pyrrolin-l-yl)-2-(3-benzoylmethylene-2-oxopiperazin-1-yl)ethanes have been obtained with 35–37% yields via reactions of benzoylpyruvic acid methyl ester with a mixture of aromatic aldehyde and diethylenetriamine in a 2: 1: 1 molar ratio.

Reaction of substituted o-aminophenols with acylpyruvic acid esters and α-ketoglutaric acid. Antibacterial activity of the products

Reaction of methyl esters of acylpyruvic acids with substituted o-aminophenols led to 6(7)-substituted 3-acylmethylene-1,4-benzoxazin-2-ones. Reaction of substituted o-aminophenols with α-ketoglutaric acid led to 6-substituted 3-carbonyl-1,4-benzoxazin-2-ones. The structures of the synthesized compounds were confirmed by IR and NMR spectroscopy and mass spectrometry. The antibacterial activity of the compounds was studied.

Synthesis and antimicrobial activity of 4-aroyl-3-hydroxy-2,5-dihydrofuran-2-ones and their derivatives

Previously we reported on substances possessing antiinflammatory [1], antiviral [2], nootropic [3], and antimicrobial [3, 4] properties in 1-substituted 5-aryl-4acyl-3-hydroxy-3-pyrrolin-2-ones. In continuation of the search for new compounds with antimicrobial activity in the series of 5-membered hydrogenated 2,3-dioxoheterocycles, we have synthesized a series of 4,5-substituted tetrahydrofurandiones in order to determine how the transition from pyrrolinediones to their closest analogs belonging to the furan series affects the antimicrobial properties. In the first stage, methyl ethers of aroylpyruvic acids were condensed with aromatic aldehydes and formalin in the presence of potassium carbonate. By acidifying these reaction mixtures according to Foldi et al. [5], we obtained 5-R-4-aroyl-3-hydroxy-2,5-dihydrofuran-2-ones (I X) with R = H or aryl. Compounds I X appear as colorless crystalline substances soluble in DMF, DMSO, glacial acetic acid, and chloroform. The IR spectra exhibit absorption bands related to double bonds (at 1600 1632 c m t), carbonyl groups of the acyl substituents (16401688 cmt ) , lactone carbonyls (1750 1760 e m l), and a broad band due to stretching vibrations of the hydroxy groups associated by intramolecular hydrogen bonds (3200 3288 cmt). The tH NMR spectra of the 5-aryl-substituted compounds display a singlet signal due to methine proton in position 5 of the heterocycle (at 6 . 5 7 6.80 ppm). A singlet signal due to protons of the methylene group at position 5 of the heterocycle in the spectrum of unsubstituted tetrahydrofuran-2,3-diones (R = H) is observed at 5.22 5.52 ppm and a multiplet related to the aromatic protons, at 7.64 8.00 ppm. The absence o f signals due to enol hydroxy groups is probably explained by considerable broadening of these signals caused by the intraand intermolecular hydrogen bonds. The

Synthesis and antimicrobial activity of n,7-diaryl-5-methyl-4,7-dihydrotetrazolo[1,5- a ] pyrimidine-6-arboxamides

N,7-Diaryl-5-methyl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxamides were synthesized by three-component reaction of acetoacetanilides (2-methylacetoacetanilide, 2,4-dimethylacetoacetanilide, 4-chloroacetoacetanilide, o-acetoacetanilide) with a mixture of aromatic aldehyde and 5-aminotetrazole. The proposed structures are confirmed by IR and PMR spectroscopy and mass spectrometry. The synthesized compounds are characterized with respect to antimicrobial activity.

Intramolecular cyclization of 5-aryl-3-arylamino-4-benzoyl-1h-3-pyrrolin- 2-ones to pyrrolo[3,4- b ]quinolines

It has been shown that 5-aryl-3-arylamino-4-benzoyl-1H-3-pyrrolin-2-ones cyclize in the presence of conc. H2SO4 to give pyrrolo[3,4-b]quinolines.

Five-membered 2,3-dioxoheterocycles 15. Synthesis and [1,3]-sigmatropic rearrangement of 1,5-diaryl-3-diphenylmethoxy-4-ethoxycarbonyl-2,5-dihydropyrrol-2-ones

Ethyl oxaloacetate reacts with a mixture of an aromatic aldehyde and an arylamine to give 1,5-diaryl-4-ethoxycarbonyltetrahydropyrrole-2,3-diones, which react with diphenyldiazomethane to give the O-alkylation products. On heating, the latter undergo suprafacial [1,3]-sigmatropic rearrangement to 1,5-diaryl-4-diphenylmethyl-4-ethoxycarbonyltetrahydropyrrole-2,3-diones. The effects of the type of migrating group on the rearrangement are discussed.